Method and apparatus for automatically pre-positioning a passenger bridge

ABSTRACT

Disclosed are a method and an apparatus for pre-identifying a model of an aircraft to which a passenger bridge is to be connected and for setting the passenger bridge to a predetermined position in dependence upon the identification. The system uses an imager to capture an image of the aircraft as it approaches the bridge. A local processor of the bridge extracts features for comparison to template data stored locally in a database for a plurality of possible aircraft models. In dependence upon a result of the comparison, a model of the aircraft is identified absent the local processor receiving additional information from an external information source. The local processor retrieves other data from the database for moving the passenger bridge to a predetermined position for the identified model of aircraft.

[0001] This application claims priority from U.S. Provisional Application Ser. No. 60/352,851 filed Feb. 1, 2002.

FIELD OF THE INVENTION

[0002] The present invention relates generally to passenger loading bridges and more particularly to a method and apparatus for pre-identifying an approaching aircraft and for automatically pre-positioning the passenger bridge in dependence upon the identification.

BACKGROUND OF THE INVENTION

[0003] In order to make aircraft passengers comfortable, and in order to transport them between the airport terminal and the aircraft in such a way that they are protected from weather and other environmental influences, passenger loading bridges are used which can be telescopically extended and the height of which is adjustable. Aircraft passenger bridges come in a wide variety of types and sizes. Some bridges have a fixed length and are pivotable radially about a fixed pivot between a stowed position and an aircraft engaging position, some bridges can be telescoped longitudinally and are pivotable radially about a fixed pivot and some bridges have a fixed length and are mounted on a stationary pedestal. An aircraft-engaging cabin is mounted on a distal end of each of the aforementioned types of bridges. Furthermore, each type of bridge has a mechanism for adjusting the vertical height of the cabin at the distal end of the bridge. The height adjustment mechanism enables an operator to change the height of the distal end of the bridge so that the cabin engages the doors of different types of aircraft at the proper location.

[0004] The height adjustment mechanism may be electromechanical, as where a motor drives a ball screw which raises or lowers the distal end of a bridge, or it may be electrohydraulic, as where a motor drives a pump which supplies fluid to extend or retract a hydraulic cylinder which raises or lowers the distal end of the bridge. In either case, a bridge-operator operates the height adjustment mechanism using a control panel in the cabin, which operates the motor in the mechanism. Optionally, some bridges have a motor control that incorporates a joystick. The joystick enables an operator to control the motor to raise or lower the cabin by moving the joystick forward or backward. Movement in one direction runs the motor in one direction and causes the height adjustment mechanism to elevate the passenger bridge, and movement in the other direction reverses the motor and causes the mechanism to lower the passenger bridge.

[0005] Before the cabin engages an aircraft, the operator manually adjusts the height of the cabin at the distal end of the bridge by moving the joystick until the mechanism has properly aligned the cabin with the aircraft door. With some systems, the operator must visually determine the proper position of the cabin with respect to an aircraft door and move the joystick until the mechanism has moved the cabin to the proper position. Of course, this adjustment requires considerable operator time, which increases airline operating costs and inconveniences passengers aboard the aircraft. As such, it is desirable to provide a system for aligning reliably a passenger bridge to an aircraft door in a reasonable period of time, thereby reducing bridge-operator time, reducing passenger waiting time and shortening the overall length of time that is required to put the aircraft back into the air.

[0006] Semi-automated passenger bridges are known in the prior art, which are equipped with controls that automatically cause the height adjustment mechanism to move the cabin to a predetermined height. One type of semi-automatic control for a vertical height adjustment mechanism includes an electric control which has a console equipped with a number of push button type switches, each of which is labeled with the name of a different type of aircraft. Actuating a switch causes the mechanism to move the passenger bridge column to a preset location so that the cabin is properly aligned with the door of the type of aircraft named on the switch label. Each switch in the console is connected to a mechanically actuated switch located adjacent the passenger bridge column. When a switch is actuated, the passenger bridge is moved until a cam mounted on the bridge column trips the mechanical switch, which interrupts power to the motor. The cam is positioned to trip the switch when the passenger bridge reaches the preset position.

[0007] It is a disadvantage of the above-mentioned prior art system that the bridge-operator must be present to press the switch for enabling the automated height adjustment. As such, the operator is required to arrive at the passenger bridge in advance of the aircraft, thereby making inefficient use of the bridge-operator's time, or alternatively the bridge-operator arrives to initiate the height adjustment after the aircraft has stopped at the gate, which inconveniences the passengers that are waiting aboard the aircraft to deplane. Accordingly, the above-mentioned system does not fully achieve the desired advantage of a semi-automated system; specifically, minimizing the time that is required in order for a bridge-operator to align the passenger bridge with the aircraft door. It is another disadvantage of the prior art that adjusting the passenger loading bridge height is performed as a part of the docking operation thereby providing little advantage over other prior art docking systems.

[0008] Other semi-automated or computer assisted docking systems are known in the prior art. Larson et al. in U.S. Pat. No. 5,257,431 teach an array of non-contact inductive sensors mounted along a front bumper of a passenger bridge. The sensors detect the close approach of the bumper to the aircraft body, and automatically reduce the approach speed of the passenger bridge to the aircraft. Further, the sensors and associated circuitry sense angular misalignment of the passenger bridge with the aircraft and selectively and automatically control its position relative to the aircraft. Of course, Larson does not teach a system for automatically pre-positioning the passenger bridge, prior to the bridge-operator arriving at the passenger bridge.

[0009] Schoenberger et al. in U.S. Pat. No. 5,226,204 describe an automated loading bridge that uses video cameras in the control of the bridge. The system maneuvers an end of the bridge to a position close to the door, whereupon a person controls the bridge, during the last part of its movement, by looking at images recorded by the video cameras.

[0010] WO 96/08411, filed Sep. 14, 1995 in the name of Anderberg, describes another semi-automatic system for controlling the movement of a passenger bridge. When an aircraft has landed at an airport, a central computer, such as for instance a central computer located within a terminal building, notes this fact and transmits information on the type of aircraft to a local computer of the passenger bridge. For instance, the central computer accesses a flight information database of the airport and retrieves information about the aircraft including the model of aircraft, the gate to which the aircraft has been assigned and the aircraft registration number. The local computer accesses a different database and retrieves additional information including information on the positions of the doors for the type of aircraft that has landed, as well as information on the expected stop position for the type of aircraft. Using the information retrieved by the local computer and the information provided by the central computer, the local computer determines an expected absolute position of the door with which the bridge is to be aligned. Accordingly, the passenger bridge is moved under computer control to a position close to the expected position of the door, for example within 2 meters. The system includes sensors for providing to the local computer real-time positional data for a cabin end of the bridge. The system further includes an electromagnetic distance meter for detecting the close approach of the passenger bridge to the aircraft and for reducing the speed of the passenger bridge in dependence thereon. Preferably, the bridge is preset to the expected position of the door before the aircraft has stopped moving.

[0011] Unfortunately, the semi-automatic system that is disclosed by Anderberg does not adequately address the problem of avoiding a collision involving the passenger bridge and an aircraft, which is a major concern to airlines and a significant obstacle to the implementation of semi- or fully-automated bridge alignment systems at airports. In particular, the information on the type of aircraft is obtained from an external information source, such as for instance the central computer located within the terminal building. Every maneuver of the passenger bridge during an alignment operation is performed in dependence upon knowing specific parameters for the instantaneous aircraft model, such as for instance the position of the door and the expected stopping position of the aircraft. Although the specific parameters for every model of aircraft are accessible locally by the local computer, only the central computer can provide information on the model of aircraft that has landed, which information may be erroneous. Although the aircraft model is confirmed using sensors disposed on the passenger bridge, said confirmation does not occur until after the aircraft has stopped moving. As such, the passenger bridge may be guided to a position that is. suitable for one model of aircraft when in fact a different model of aircraft has landed. In an extreme case, the passenger bridge may be moved into a position in which it collides with the aircraft. Of course even if a collision is avoided, then additional operator time is required to align the passenger bridge after the aircraft has stopped moving and the aircraft model is correctly identified.

[0012] It is a further disadvantage of the system described by Anderberg that the central computer may serve a plurality of different passenger bridges at an airport. As such, if there is a problem with the central computer then every one of the passenger bridges in communication therewith will go offline, and automated alignment will not be possible. Of course, a highly automated airport is unlikely to retain a sufficient number of bridge-operators to manually align every passenger bridge until the system is repaired. It will therefore be necessary to ‘mirror’ the central computer using a redundant computer system, which adds unnecessary expense. Alternatively, as suggested by Anderberg, the information on aircraft model is provided via a local data input device every time a flight arrives. Of course, a system in which a human must provide the aircraft model carries a greatly increased risk that an incorrect aircraft model will be provided as a result of human error, particularly when similar designations such as “707”, “727”, “737”, “757”, etc. have been used to identify aircraft models.

[0013] Still another disadvantage of the system disclosed by Anderberg is that the central computer requires access to a flight information database of the airport. Such a database must be set up to be accessible by the central computer, and there may be serious security-related issues involved with providing widely distributed access to flight database information. Furthermore, many airports around the world do not currently support a database that would be suitable for interfacing with a passenger bridge system as described by Anderberg. In those cases, the authorities considering an automated passenger bridge system would demand a system capable of completely autonomous operation.

[0014] What is required is a system for identifying a type of aircraft absent externally provided information, and for performing automatically an initial portion of a passenger loading bridge alignment operation absent bridge-operator intervention, such that when the bridge-operator arrives only a final alignment to engage the passenger bridge with the aircraft fuselage remains to be performed manually. It would be further advantageous to provide a system which confirms an initial identification of a type of aircraft during the time period in which the aircraft is moving toward the passenger bridge, such that the pre-set passenger bridge position is better optimized by the time the aircraft stops moving, and such that the risk of a collision involving the passenger bridge and the aircraft is minimized.

OBJECT OF THE INVENTION

[0015] In an attempt to overcome these and other limitations of the prior art it is an object of the instant invention to provide an apparatus for moving a passenger bridge under computer control to a pre-position for engaging an aircraft.

[0016] It is another object of the instant invention to provide an apparatus for moving a passenger bridge under computer control to a pre-position for engaging an aircraft in dependence upon an identified model of aircraft.

[0017] It is still another object of the instant invention to provide an apparatus for moving a passenger bridge under computer control to a pre-position for engaging an aircraft absent information from an external information source.

SUMMARY OF THE INVENTION

[0018] In accordance with the instant invention there is provided an apparatus for pre-positioning a passenger bridge comprising:

[0019] a) a passenger bridge having a first end moveable for abutting an aircraft and a second end for fixedly engaging a building;

[0020] b) an imager for capturing an image of the aircraft and for providing a signal in dependence upon the captured image, the signal comprising data indicative of an aircraft type;

[0021] c) a processor in communication with the imager for receiving the signal therefrom and for extracting the data indicative of an aircraft type;

[0022] d) a memory in communication with the processor for storing template data indicative of an aircraft type for each of a plurality of different aircraft types and for providing said data to the processor for comparison with the extracted data, the aircraft type being identifiable in dependence upon a result of the comparison and absent additional information being provided during use from an external source; and,

[0023] e) an actuator in communication with the processor for receiving therefrom a control signal in dependence upon the identified aircraft type, the actuator for pre-positioning the first end of the passenger bridge to a predetermined position in dependence upon the control signal.

[0024] In accordance with another aspect of the instant invention there is provided a method of pre-setting the position of a passenger bridge comprising the steps of:

[0025] a) using an imager, capturing an image of an aircraft having a door;

[0026] b) characterizing the captured image to extract at least a feature indicative of a type of the aircraft;

[0027] c) comparing the extracted at least a feature to template data stored in a memory so as to identify a first type of the aircraft in dependence upon a result of the comparison and absent additional information being provided during use from an external source;

[0028] d) retrieving other data stored in the memory, the other data relating to a pre-position for the passenger bridge relating to a position of the door of the first type of the aircraft; and,

[0029] e) automatically moving the passenger bridge in a direction toward the pre-position in dependence upon the retrieved other data.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Exemplary embodiments of the invention will now be described in conjunction with the following drawings, in which similar reference numbers designate similar items:

[0031]FIG. 1 shows a schematic top view of a passenger bridge in a stowed position and including an apparatus according to the instant invention for pre-positioning the passenger bridge;

[0032]FIG. 2 shows a schematic top view of the passenger bridge of FIG. 1 in a pre-position for engaging an aircraft;

[0033]FIG. 3 shows a schematic top view of the passenger bridge of FIG. 1 in an aircraft engaging position;

[0034]FIG. 4 is a more detailed view of a part of the passenger bridge close to the body of an aircraft;

[0035]FIG. 5 shows a schematic top view of passenger bridge in a stowed position and equipped with a prior art apparatus for pre-positioning the bridge;

[0036]FIG. 6 shows a simplified flow diagram of a method of presetting the position of a passenger bridge relative to an expected stopping position of an aircraft, according to the prior art;

[0037]FIG. 7 shows a simplified flow diagram of a method of presetting the position of a passenger bridge relative to an expected stopping position of an aircraft, according the instant invention;

[0038]FIG. 8 shows a simplified flow diagram of another method of presetting the of a passenger bridge relative to an expected stopping position of an aircraft, according the instant invention;

[0039]FIG. 9 shows a simplified flow diagram of still another method of presetting the position of a passenger bridge relative to an expected stopping position of an aircraft, according the instant invention.

DETAILED DESCRIPTION OF THE INVENTION

[0040] The following description is presented to enable a person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and the scope of the invention. Thus, the present invention is not intended to be limited to the embodiments disclosed, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

[0041] Referring to FIG. 1, shown is a schematic top view of a passenger bridge including an apparatus according to the instant invention for pre-positioning the passenger bridge. The passenger bridge 1, shown in a stowed position, comprises a rotunda 2, which is connected to a terminal building 3 and from which extends a passageway 4. The passageway 4 ends with a pivotable cabin 5 and includes inner 16 and outer 17 passageway elements, wherein the inner element 16 is telescopically received within the outer element 17 such that the length of the passageway 4 is variable. Of course, each passageway element includes a left sidewall, a right sidewall, a floor member and a ceiling member. Optionally, a number of passageway elements other than two are provided. A control panel 8 is disposed within the cabin 5 for use by a bridge-operator to adjust the bridge under manual control.

[0042] The passenger bridge 1 is adjustable for connection to an aircraft, which aircraft approaches along approach line 19. To this end, and as shown in FIG. 4, the passenger bridge 1 includes a bogie 30 with driving wheels 31 for achieving angular displacement of the passenger bridge as well as for telescoping of the passageway elements to alter the length of the passenger bridge 1. Referring again to FIG. 1, the passageway 4 is suspended from a frame 6 for adjusting the height of the passenger bridge 1. Finally, the passenger bridge 1 includes an actuator (not shown) for pivoting the cabin 5. Accordingly, the cabin 5 is alignable to a door opening of a plurality of different aircraft models by adjusting the height, length, etc. of the passenger bridge 1.

[0043] Referring now to FIG. 2, shown is a schematic top view of the passenger bridge of FIG. I in a pre-position for connecting to a door 20 of an aircraft 21. Preferably, the passenger bridge is moved into the pre-set position during a period of time in which the aircraft 21 is taxiing toward the passenger bridge 1 along approach line 19.

[0044] Of course, passengers aboard the plane are prevented from deplaning until the passenger bridge 1 is moved from the pre-position into an aircraft engaging position, which position is shown in FIG. 3. Before the passenger bridge 1 can be moved safely into the aircraft engaging position, however, the plane must come to a complete stop. As such, passengers aboard the aircraft are required to wait even after the aircraft has stopped moving. Accordingly, it is desirable to optimize the passenger bridge pre-position, in dependence upon the model of an aircraft, such that engaging the aircraft after it has stopped moving is a straightforward and rapid process.

[0045] The apparatus according to the instant invention for pre-positioning the passenger bridge 1 will now be described in detail with reference to FIGS. 1-3. An imager 18, for instance an imager in the form of a laser range finder, is disposed close to a cabin end of the passenger bridge 1 for capturing an image of the aircraft 21. Optionally, the image 18 is in the form of a video camera. In a most preferred embodiment, the imager 18 is for capturing a plurality of images of the aircraft 21 before the aircraft comes to a stop at a position adjacent to the passenger bridge 1. In communication with the imager 18 is a local computer 7 for receiving the plurality of captured images therefrom. Optionally, the local computer 7 receives a sub-set of the plurality of images, each image of the sub-set of images received at a different time, one from the other. The local computer 7 is also in communication with a memory storage area 9, which contains a database of information including door height and other data relating to a plurality of different aircraft models to which the bridge is to be connected. The local computer 7 is for processing the received captured images to extract features of the imaged aircraft and for comparing the extracted features to stored features for each of the plurality of different aircraft models, to thereby identify the model of the imaged aircraft. Further, the local computer 7 is for retrieving information from the memory storage area 9 relating to an expected stopping position and a position of a door on the aircraft to which the bridge is to be connected, in dependence upon a result of the identification. Accordingly, the local computer 7 can determine an absolute expected stopping position of a door on the aircraft 21, absent information from an external source and prior to the aircraft coming to a stop at a position adjacent to the bridge 1.

[0046] The passenger bridge 1 further comprises first, second and third transducers 10, 11 and 12 for determining the angular position of the passageway, the height of the passageway and the relative positions of the passageway elements, respectively. The bridge also includes a fourth transducer 13 for sensing the angular position of the cabin 5. Of course, other types of transducers and/or other numbers of transducers are optionally used to determine the position of the bridge. For instance, a laser (not shown) may be mounted on the roof of the cabin 5, as may at least two reflectors (not shown) on different locations on the terminal building. By sweeping the laser, measuring the distance to the reflectors with the aid of the laser, and determining the angular position of the laser when directed toward the reflectors, the position of the cabin 5 may be determined. As the position of the cabin 5 is known, the local computer 7 can determine a movement of the passenger bridge 1 for moving the passenger bridge 1 from the stowed position to a predetermined pre-position, close to the expected stopping position of the door 20. Of course, a different pre-position is required for different models of aircraft having different expected stopping positions, different door heights, etc.

[0047] Preferably, the passenger bridge 1 further comprises an electromagnetic distance meter 14 for sensing the close approach of the passenger bridge to the aircraft 21. Optionally, the distance meter 14 provides a signal to the local computer 7 for automatically reducing and/or otherwise controlling the rate of approach of the passenger bridge 1 to the aircraft 21 when within a predetermined distance. As such, the passenger bridge 1 is moveable to the aircraft 21 using a substantially continuous movement, such that the pre-positioning thereof is fluid as opposed to static. Further optionally, a pressure sensor 15 is provided along a bumper at the cabin end of the passenger bridge 1 for sensing engagement with the aircraft 21. Of course, the distance meter 14 and the pressure sensor 15 are effective only at very close approach to the aircraft 21, and as such they do not constitute a reliable system for collision avoidance absent the imager 18.

[0048] Referring now to FIG. 5, shown is a schematic top view of a passenger bridge at a pre-position and equipped with a prior art apparatus for pre-positioning the passenger bridge. Drawing elements shown in FIG. 5 having identical form and function as those drawing elements described previously with reference to FIGS. 1 to 3 have been assigned identical reference numerals, and their description is omitted here in the interest of brevity. The apparatus according to the prior art further comprises a central computer 41 in communication with the local computer 7 via a communication link 43. The central computer 41 is in communication with a flight information database 42, for receiving therefrom information on the model of the aircraft 21 to which the bridge is to be connected. The central computer provides said information to the local computer 7 via the communication link 43. The local computer 7 receives the transmitted data and accesses database 9 to retrieve information on the expected stopping position and door position for the model of aircraft that is expected. Using the information received from the central computer 41 and the information retrieved from the database 9, the local computer is able to determine an absolute expected stopping position for the door 20 of the aircraft 21. The local computer 7 provides a control signal for actuating the passenger bridge 1 to a pre-position close to the expected stopping position. After the aircraft has stopped moving, the electromagnetic sensors 14 are used to confirm the model and stopping position of the aircraft 21.

[0049] Referring now to FIG. 6, shown is a simplified flow diagram for a method of pre-positioning a passenger bridge relative to an expected stopping position of an aircraft door according to the prior art. When an aircraft 21 has landed, a central computer 41 at step 100 transmits information on the model of aircraft to a local computer 7 of the passenger bridge 1. The central computer 41 is, for instance, a central computer located within a terminal building 3 of an airport and is in communication with a flight information database 42 of the airport. The local computer 7 accesses a local database 9 and at step 101 retrieves information on the position of a door for the model of aircraft that is taxied in direction of a bridge, as well as information on the expected stopping position for the model of aircraft. The retrieved information allows the local computer at step 102 to move the passenger bridge to a position close to an expected position of the door when the aircraft has stopped moving. After the aircraft has stopped moving at step 103, the model of the aircraft is confirmed at step 104. If it is determined at decision step 105 that the aircraft is not of the expected model, an error message is generated at step 106, the system shuts down at step 107, and the system awaits the arrival of a bridge-operator to perform the remainder of the alignment manually. If at decision step 105 the aircraft model is confirmed to be the expected model, then the system shuts down normally or enters a standby mode of operation at step 107.

[0050] It is a disadvantage of the prior art system that a central computer 41 provides information on the model of aircraft to the local computer 7. As discussed supra if there is a problem with the central computer 41 then every passenger bridge 1 in communication therewith will go offline, and automated alignment will not be possible. Further, the central computer 41 requires access to a flight information database 42 of the airport. Such a database must be set up to be accessible by the central computer 41, and there may be serious security-related issues involved with providing widely distributed access to flight database information.

[0051] Also, such a bridge is only useful with some airport systems and cannot support all airports without supporting many different airport computer interfaces. Further, such a system requires modification of the airport system and, as such, is more costly to implement on a trial basis for a single passenger loading bridge since the computer system of the airport requires modification whether one bridge or ten bridges are installed. Also, some airports do not provide for computer database access for security reasons and, in light of recent events, are unlikely to change this policy.

[0052] Referring now to FIG. 7, shown is a simplified flow diagram for a method of pre-positioning a passenger bridge relative to an expected stopping position of an aircraft door, according to the instant invention. When an aircraft is taxied in direction of a bridge, a sensor 18 of the passenger bridge 1 detects the aircraft and captures an image at step 110. The image is transmitted to a local computer 7, which performs image-processing to determine if the object is an aircraft. When it is confirmed at decision step 111 that the object is an aircraft, the local computer 7 performs additional processing at step 112 in order to identify the model of aircraft. If it is not possible at decision step 113 to confirm a specific aircraft model within a predetermined confidence limit, then additional images are captured by the sensor 18 as the aircraft 21 continues to approach the passenger bridge 1, and the additional images are transmitted to the local computer 7 in order to positively identify the aircraft model prior to the aircraft 21 arriving at the gate area.

[0053] Once the aircraft model has been positively identified, the local computer 7 accesses a local database 9 and at step 114 retrieves information on the position of a door for the model of aircraft that is taxied in direction of a bridge, as well as information on the expected stopping position for the model of aircraft. The retrieved information allows the local computer at step 115 to move the passenger bridge to a position close to an expected position of the door when the aircraft has stopped moving. The system waits at step 116 for the aircraft to come to a complete stop, and the system enters a standby mode of operation at step 117. Optionally, after the aircraft has come to a complete stop at step 116, a step of confirming the identified aircraft model is performed.

[0054] In a particularly preferred embodiment, the step 112 of identifying the aircraft model includes the steps of: using the local computer 7, extracting features from the captured image and comparing the extracted features to stored features retrieved from the database 9, for each of a plurality of different aircraft models. A “match score” is determined in dependence upon a result of the comparison, such as for instance a probability that the aircraft 21 is correctly identified as a particular aircraft model. A probability lower than a predetermined value is sufficient to eliminate a model of aircraft. In order for the aircraft 21 to be positively identified, the local computer 7 must eliminate all but one model of aircraft as described above. Additionally, the aircraft 21 preferably agrees with or “match” stored data to within a predetermined confidence level in order to be positively identified as a specific model of aircraft. Accordingly, the passenger bridge 1 does not move to a pre-position based on a 60% chance that the aircraft 21 is a Boeing 737. Preferably, greater than 95% certainty and even more preferably greater than 99% certainty that aircraft 21 is a particular model of aircraft would be required before the passenger bridge 1 is moved to a pre-position.

[0055] Advantageously, the method according to FIG. 7 permits the aircraft 21 to be identified at an early point of its approach to the passenger bridge 1 when operating conditions are favorable. If conditions are less favorable, however, the aircraft is identified using a process of elimination and confirmation as the aircraft 21 continues to approach the passenger bridge 1. As the passenger bridge 1 remains in the stowed position until the aircraft 21 has been identified, the risk that the passenger bridge will collide with the aircraft is reduced. Further advantageously, the system permits setting the passenger bridge 1 to a preset position, absent receiving additional information from an external source, such as an airport flight information database.

[0056] Referring now to FIG. 8, shown is a simplified flow diagram of another method of pre-positioning a passenger bridge relative to an expected stopping position of an aircraft door, according to the instant invention. When an aircraft is taxied in direction of a bridge, a sensor 18 of the passenger bridge 1 detects the aircraft and captures an image at step 120. The image is transmitted to a local computer 7, which performs image-processing to determine if the object is an aircraft. Preferably, the sensor 18 captures a plurality of images at step 120 and at least a selected image of the plurality of images is transmitted to a local computer 7. When it is confirmed at decision step 121 that the object is an aircraft, the local computer 7 performs additional image-processing at step 122 in order to identify a “most probable” model of aircraft. For instance, the local computer 7 extracts features indicative of a model of the aircraft from the image and compares the extracted features to template data retrieved from the database 9 for each of a plurality of different types of aircraft. At step 123 the local computer 7 retrieves other information from database 9 relating to a pre-position for the “most probable” model of aircraft, and at step 124 the passenger bridge 1 begins moving toward the pre-position in dependence upon the retrieved other data.

[0057] If it is determined at decision step 125 that the model of aircraft has not been identified to within a predetermined confidence limit, then the local computer determines if the aircraft has approached to within a predetermined safety perimeter around the passenger bridge at decision step 129. If it is determined that the aircraft is inside the perimeter, then there is insufficient time to safely complete the pre-positioning operation and the local computer 7 automatically retracts the passenger bridge to a safe position at step 142, the system is placed into a standby mode of operation at step 128, and a bridge-operator performs the alignment manually. Alternatively, if it is determined that the aircraft is outside the perimeter, then the sensor 18 captures a new image of the aircraft 21 and the steps 122 to 125 are repeated. When the aircraft model is positively identified at decision step 125, the local computer 7 finishes moving the passenger bridge to the pre-position at step 126, waits for the aircraft 21 to come to a stop at a position adjacent to the passenger bridge 1 at step 127, and places the system into a standby mode of operation at step 128. Optionally, the local computer 7 confirms an initial identification of the model of aircraft by re-determining the model of aircraft in dependence upon additional images provided from the sensor 18 prior to the aircraft 21 stopping at the expected stop position adjacent the passenger bridge 1.

[0058] Optionally, the local computer 7 controls the rate of approach of the passenger bridge 1 to the pre-position, such that the aircraft comes to a stop at the expected stop position prior to the passenger bridge 1 arriving at the pre-position. Further optionally, in a system which includes a device for automatically engaging the passenger bridge 1 to the fuselage of the aircraft 21, the bridge is advantageously moved from the pre-position to an aircraft engaging position, absent a step of stopping the bridge at the pre-position. Such a smooth transition from the pre-position operation to the aircraft-engaging operation, absent the step of stopping the passenger bridge at the pre-position, reduces passenger bridge skidding on wet and/or slippery surfaces, reduces wear-and-tear of the passenger bridge components, etc.

[0059] It is an advantage of the method according to FIG. 8 that the passenger bridge 1 is moved to a pre-position before the aircraft stops moving, wherein the pre-position is optimized in an iterative fashion while the passenger bridge is in motion, until the aircraft model is positively identified to within a predetermined confidence limit. As such, the passenger bridge is not pre-positioned accidentally to a position where a collision could occur, for example as a result of misidentification of the aircraft model. Further advantageously, the system permits pre-positioning of the passenger bridge 1, absent receiving additional information from an external source, such as an airport flight information database. It is a further advantage of the method of FIG. 8 that by starting to move the bridge early, for instance prior to positively identifying the model of the aircraft, the passenger bridge may be moved at a slower rate compared to the prior art methods. The aircraft model is identified to within a predetermined confidence limit during a period of time in which the bridge is moving slowly in a direction that is generally toward the expected stop position of the aircraft, along a path that is altered from time to time by the local computer 7 in dependence upon the identification.

[0060] Referring now to FIG. 9 shown is a simplified flow diagram of another method of pre-positioning a passenger bridge 1 relative to an expected stop position of an aircraft door, according to the instant invention. When an aircraft is taxied in direction of a bridge, a sensor 18 of the passenger bridge 1 detects the aircraft and captures an image at step 130. The image is transmitted to a local computer 7, which performs image-processing to determine if the object is an aircraft. Preferably, the sensor 18 captures a plurality of images at step 130 and at least a selected image of the plurality of images is transmitted to a local computer 7. When it is confirmed at decision step 131 that the object is an aircraft, the local computer 7 performs additional image-processing at step 132 in order to identify the type of the aircraft. For instance, the local computer 7 extracts features indicative of a type of the aircraft from the image and compares the extracted features to template data retrieved from the database 9 for each of a plurality of different types of aircraft. The type of the aircraft is selected preferably from a hierarchal set of classifications, some types in the hierarchy representative of larger types of aircraft, while other types in the hierarchy representative of smaller types of aircraft. Each type of the aircraft includes at least a unique model of aircraft, wherein each unique model of aircraft within a same type has a substantially similar pre-positioning specification.

[0061] If it is determined at decision step 133 that the type of aircraft has been identified as a unique model of aircraft to within a predetermined confidence level, then the local computer 7 retrieves at step 137 other data from database 9 relating to a final pre-position for the identified model of aircraft, finishes moving the passenger bridge 1 to the final pre-position at step 138, and then waits at step 139 for the aircraft 21 to come to a stop at a position adjacent to the passenger bridge 1. The system is placed into a standby mode of operation at step 140.

[0062] Alternatively, if it is determined at decision step 133 that the type of aircraft has not been identified as a unique model of aircraft to within a predetermined confidence level, then the local computer determines if the aircraft has approached to within a predetermined safety perimeter around the passenger bridge at decision step 134. If it is determined that the aircraft is inside the perimeter, then there is insufficient time to safely complete the pre-positioning operation and the local computer 7 automatically retracts the passenger bridge to a safe position at step 141, the system is placed into a standby mode of operation at step 128, and a bridge-operator performs the alignment manually. Alternatively, if it is determined that the aircraft is outside the perimeter, then at step 135 the local computer 7 retrieves other data from the database 9 relating to a pre-position for the identified type of aircraft, and begins moving the passenger bridge 1 to the pre-position at step 136. The sensor 18 captures a new image of the aircraft 21 and the steps 132 to 136 are repeated until the unique aircraft model is positively identified. When the unique aircraft model is positively identified at decision step 133, the local computer 7 retrieves at step 137 other data from database 9 relating to a final pre-position for the identified model of aircraft, finishes moving the passenger bridge 1 to the final pre-position at step 138, and then waits at step 139 for the aircraft 21 to come to a stop at a position adjacent to the passenger bridge 1. The system is placed into a standby mode of operation at step 140. Optionally, the local computer 7 confirms an initial identification of the model of aircraft by re-determining the model of aircraft in dependence upon additional images provided from the sensor 18 prior to the aircraft 21 stopping at the expected stop position adjacent the passenger bridge 1.

[0063] Optionally, the local computer 7 controls the rate of approach of the passenger bridge 1 to the pre-position, such that the aircraft comes to a stop at the expected stop position prior to the passenger bridge 1 arriving at the pre-position. Further optionally in a system which includes a device for automatically engaging the passenger bridge 1 to the fuselage of the aircraft 21, the bridge is advantageously moved from the pre-position to an aircraft engaging position, absent a step of stopping the bridge at the pre-position. Such a smooth transition from the pre-position operation to the aircraft-engaging operation, absent the step of stopping the passenger bridge at the pre-position, reduces passenger bridge skidding on wet and/or slippery surfaces, reduces wear-and-tear of the passenger bridge components, etc.

[0064] It is an advantage of the method according to FIG. 9 that the passenger bridge begins moving to a pre-position that is suitable for a type or type of aircraft, i.e. a large aircraft or a small aircraft, before the aircraft stops moving. The pre-position is optimized subsequently until an exact model of the aircraft 21 has been determined to within a predetermined confidence limit. As such, the passenger bridge is not accidentally pre-positioned to a position where a collision could occur due to incorrect identification of the aircraft model. Further advantageously, the system permits setting the passenger bridge 1 to a pre-position, absent receiving additional information from an external source, such as an airport flight information database. It is a further advantage of the method of FIG. 9 that by starting to move the bridge early, for instance prior to positively identifying the unique model of the aircraft, the passenger bridge may be moved at a slower rate compared to the prior art methods. The aircraft model is identified to within a predetermined confidence limit during a period of time in which the bridge is moving slowly in a direction that is generally toward the expected stop position of the aircraft, along a path that is altered from time to time by the local computer 7 in dependence upon the identification.

[0065] It is a further advantage of each of the methods of FIGS. 7 to 9 that a substantial portion of the passenger loading bridge alignment operation is performed prior to the aircraft 21 coming to a stop at a position adjacent to the passenger bridge 1. In other words, the bridge is moving while the aircraft is still taxiing, which reduces passenger waiting time after the plane has stopped and also reduces the speed at which the passenger loading bridge must move thereby rendering its operation safer for the aircraft and for ground crew operating near the aircraft and the passenger loading bridge. Further advantageously, absent the local computer 7 correctly identifying the model of aircraft 21, the sensor 18 provides the necessary information for pre-positioning the passenger bridge 1 to a correct height for the aircraft 21. As such, the passenger bridge 1 is pre-positioned to a correct height before a bridge-operator arrives, even when substantially manual bridge alignment is necessary.

[0066] It is still a further advantage of the methods of FIGS. 8 and 9 that as the aircraft continues to approach the passenger bridge 1, the local computer 7 optionally “tunes” a previous estimate and thereby optimizes the initial pre-positioning of the passenger bridge 1. Accordingly, the passenger bridge 1 begins moving into the preposition before a final, positive identification of the aircraft model has been made. The initial pre-position is subsequently optimized as the sensor 18 captures additional images of the aircraft 21, which images provide more accurate information for identifying the model of aircraft. Of course, the movements of the passenger bridge that are required to optimize the pre-position are smaller than the initial movements that are required to move the passenger bridge from the stowed position to the initial pre-position. Advantageously, identifying the aircraft 21 before it comes to a stop at a position adjacent to the passenger bridge 1 allows the passenger bridge to begin moving into the pre-position earlier. As such, slower motors may be used to move the passenger bridge, which reduces the cost of producing and maintaining the bridge, and which provides additional safety during operation of the bridge.

[0067] Optionally, the apparatus according to the instant invention comprises a kit for retrofitting an existing moveable passenger bridge. For instance, apparatus components including a sensor 18, a local computer 7 in operative communication with the sensor 18, a memory 9 in operative communication with the local computer 7, and a transmitter (not shown) in operative communication with the local computer 7 are integrated into a single unit for being disposed on the existing moveable passenger bridge. Optionally, the individual components are provided separately for being disposed on the exiting moveable bridge. The transmitter is selected from a group including but not limited to: a wireless transmitter, an optical transmitter, an infrared transmitter and a transmitter having wires for connection to a receiving device. The transmitter is for providing control signals from the local computer 7 to an existing bridge actuating mechanism of the existing moveable passenger bridge in a form that is recognizable thereby.

[0068] Numerous other embodiments may be envisaged without departing from the spirit and scope of the invention. 

What is claimed is:
 1. An apparatus for moving an end of a moveable passenger bridge to a pre-position proximate an expected stop position of a door on an aircraft, the apparatus comprising: an imager for capturing a plurality of images of the aircraft and for providing a plurality of respective signals; a processor in communication with the imager for receiving the plurality of respective signals, for providing a determination of a type of the aircraft for each signal of the plurality of respective signals in dependence upon a database of known types of aircraft and for providing a control signal related to a pre-position of the end of the moveable passenger bridge for each signal in dependence upon the determination of the type of the aircraft; and, an actuator in communication with the processor for receiving the control signal and for moving the end of the moveable passenger bridge in dependence thereon, the bridge movable along a first path determined in dependence upon a first received control signal to a second other path determined in dependence upon a second other received control signal.
 2. An apparatus according to claim 1, comprising memory in communication with the processor for retrievably storing the database of known types of aircraft, the database including information relating to the pre-position of the end of the moveable passenger bridge for each known type of aircraft.
 3. An apparatus according to claim 1, wherein the imager comprises a laser imager.
 4. An apparatus according to claim 1, wherein the imager comprises a video camera for capturing video pictures of the aircraft.
 5. An apparatus according to claim 1, comprising a sensor for sensing a distance of the aircraft relative to the end of the moveable passenger bridge and for providing a third control signal to the processor relating to the sensed distance, the third control signal for use by the processor to control a rate of approach of the end of the moveable passenger bridge to the pre-position such that a movement of the end of the moveable passenger bridge is substantially continuous to the pre-position.
 6. An apparatus for being attached to a moveable passenger bridge having a bridge actuating mechanism, the apparatus for moving an end of the moveable passenger bridge to a pre-position proximate an expected stop position of a door on an aircraft, comprising: an imager for being disposed on the moveable passenger bridge, for capturing a plurality of images of the aircraft and for providing a plurality of respective signals; a processor in operative communication with the imager for receiving the plurality of respective signals, for providing a determination of a type of the aircraft for each signal of the plurality of respective signals in dependence upon a database of known types of aircraft, and for providing a control signal related to a pre-position of the end of the moveable bridge for each signal in dependence upon the determination of the type of the aircraft; a memory in operative communication with the processor for retrievably storing the database of known types of aircraft, the database including information relating to the pre-position of the end of the moveable passenger bridge for each known type of aircraft; and, a transmitter in operative communication with the processor for receiving the control signal and for providing the plurality of control signals to the bridge actuating mechanism in a form recognizable thereby, wherein, in use, the bridge actuating mechanism moves the end of the moveable passenger bridge along a first path determined in dependence upon a first control signal and along a second other path determined in dependence upon a second other control signal; and, wherein an end-point of the second other path is the pre-position proximate the expected stop position of the door on the aircraft.
 7. An apparatus according to claim 6, wherein the apparatus is an integrated unit for being attachable to the moveable passenger bridge.
 8. A method of pre-positioning one end of a moveable bridge in relation to an expected stopping position of an aircraft comprising the steps of: a) determining a type of the aircraft; b) determining a bridge trajectory for moving the one end of the moveable bridge toward a pre-position in dependence upon the determined type of the aircraft; c) automatically moving the one end of the moveable bridge along the determined bridge trajectory toward the pre-position; d) re-determining a type of the same aircraft; and, e) altering the bridge trajectory in dependence upon the re-determined type of the same aircraft.
 9. A method according to claim 8, wherein the step d) is performed while moving the one end of the moveable bridge and wherein the step e) of altering the bridge trajectory is performed in a continuous manner and absent a step of stopping a motion of the one end of the moveable bridge.
 10. A method according to claim 8, comprising the steps of: f) iterating steps d) to e) until a unique model of the aircraft is determined to within a predetermined confidence limit; and, g) automatically moving the one end of the moveable bridge to a final pre-position along a final trajectory, in dependence upon the determined unique model of the aircraft.
 11. A method according to claim 10, wherein the steps d) to g) are performed during a period of time prior to the aircraft stopping at the expected stopping position.
 12. A method according to claim 11, wherein step g) includes the step of: g1) stopping the one end of the moveable bridge at the final pre-position.
 13. A method according to claim 11, wherein step g) includes the step of: g1) reducing a rate of movement of the one end of the moveable bridge along the final trajectory in a direction toward the final pre-position prior to the one end of the moveable bridge arriving at the final pre-position.
 14. A method according to claim 13, wherein step g) includes the step of: g2) stopping the one end of the moveable bridge at the final pre-position.
 15. A method according to claim 13, wherein the reduced rate of movement of the one end of the moveable bridge along the final trajectory is such that the plane stops at the expected stopping position prior to the one end of the moveable bridge arriving at the final pre-position and wherein the movement of the one end of the moveable bridge along the final trajectory is continuous past the final pre-position.
 16. A method according to claim 8, comprising the step of: f) iterating steps d) to e) until the type of the aircraft is determined to within a predetermined confidence limit, wherein the type of the aircraft comprises a group of aircraft models, each aircraft model within a same group having a substantially similar pre-positioning specification.
 17. A method according to claim 16, comprising the step of: g) automatically moving the one end of the moveable bridge to a final pre-position along a final trajectory, in dependence upon the substantially similar pre-positioning specification.
 18. A method according to claim 17, wherein the steps d) to g) are performed during a period of time prior to the aircraft stopping at the expected stopping position.
 19. A method according to claim 18, wherein step g) includes the step of: g1) stopping the one end of the moveable bridge at the final pre-position.
 20. A method according to claim 18, wherein step g) includes the step of: g1) reducing a rate of movement of the one end of the moveable bridge along the final trajectory in a direction toward the final pre-position prior to the one end of the moveable bridge arriving at the final pre-position.
 21. A method according to claim 20, wherein step g) includes the step of: g2) stopping the one end of the moveable bridge at the final pre-position.
 22. A method according to claim 20, wherein the reduced rate of movement of the one end of the moveable bridge along the final trajectory is such that the plane stops at the expected stopping position prior to the one end of the moveable bridge arriving at the final pre-position and wherein the movement of the one end of the moveable bridge along the final trajectory is continuous past the final pre-position.
 23. A method according to claim 8, comprising the steps prior to step e) of: d1) determining a distance of the aircraft relative to the one end of the moveable bridge; and, d2) when the determined distance is less than a predetermined threshold value, automatically moving the one end of the moveable bridge to a predetermined safe position.
 24. A method according to claim 8, wherein step of a) determining a type of the aircraft comprises the steps of: a1) using an imager, capturing an image of the aircraft; a2) characterizing the captured image to extract at least a feature indicative of the type of the aircraft; and, a3) comparing the extracted at least a feature to template data stored in a memory so as to determine the type of the aircraft in dependence upon a result of the comparison and absent additional information being provided during use from an external source.
 25. A method according to claim 24, wherein the type of the aircraft is selected from a hierarchal set of classifications, some types in the hierarchy representative of larger types of aircraft, while other types in the hierarchy representative of smaller types of aircraft.
 26. A method according to claim 24, wherein the type of the aircraft comprises a unique aircraft model.
 27. A method according to claim 24, wherein the imager comprises a laser imager.
 28. A method according to claim 8, wherein step of b) determining a bridge trajectory comprises the step of: b1) retrieving data stored in a memory, the data relating to a pre-position for the one end of the moveable bridge relating to the determined type of the aircraft.
 29. A method according to claim 24, wherein step of d) re-determining a type of the same aircraft comprises the steps of: d1) using the imager, capturing another image of the same aircraft; d2) characterizing the captured another image of the same aircraft to extract at least another feature indicative of the type of the same aircraft, the at least another feature being one of identical and other than identical to the at least a feature; and, d3) comparing the extracted at least another feature to template data stored in the memory so as to re-determine the type of the same aircraft in dependence upon a result of the comparison and absent additional information being provided during use from an external source.
 30. A method according to claim 29, wherein the type of the aircraft is selected from a hierarchal set of classifications, some types in the hierarchy representative of larger types of aircraft, while other types in the hierarchy representative of smaller types of aircraft.
 31. A method according to claim 29, wherein the type of the same aircraft comprises a unique aircraft model.
 32. A method according to claim 29, wherein the imager comprises a laser imager.
 33. A method according to claim 8, wherein step of e) altering the bridge trajectory in dependence upon the re-determined type of the same aircraft comprises the steps of: e1) when the re-determined type of the same aircraft is different than the determined type of the aircraft, determining a correction for altering the bridge trajectory in dependence upon the re-determined type of the same aircraft; and, e2) altering the bridge trajectory to guide the one end of the moveable bridge toward a different pre-position in dependence upon the re-determined type of the same aircraft.
 34. A method according to claim 8, wherein step of e) altering the bridge trajectory in dependence upon the re-determined type of the same aircraft comprises the steps of: e1) when the re-determined type of the same aircraft is the same as the determined type of the aircraft to within a predetermined confidence limit, continuing a motion of the bridge along a same bridge trajectory.
 35. A method of pre-positioning one end of a moveable bridge in relation to an expected stopping position of a door on an aircraft comprising the steps of: a) using an imager, capturing an image of the aircraft; b) characterizing the captured image to extract at least a feature indicative of a type of the aircraft; c) comparing the extracted at least a feature to template data stored in a memory so as to identify a model of the aircraft in dependence upon a result of the comparison and absent additional information being provided during use from an external source; d) iterating the steps a) through c) until a result of the comparison is indicative of a unique model of the aircraft to within a predetermined confidence limit; e) retrieving other data stored in the memory, the other data relating to a pre-position for the one end of the moveable bridge relating to an expected stopping position of the door of the unique model of the aircraft; and, f) automatically moving the one end of the moveable bridge along a path in a direction toward the pre-position in dependence upon the retrieved other data.
 36. A method according to claim 35, wherein the steps a) through f) are performed during a period of time prior to the aircraft stopping at a position adjacent the one end of the moveable bridge.
 37. A method according to claim 36, wherein step f) includes the step of f1) stopping the one end of the moveable bridge at the pre-position.
 38. A method according to claim 36, wherein step f) includes the step of: f1) reducing the rate of approach of the one end of the moveable bridge to the pre-position prior to the one end of the moveable bridge arriving at the pre-position.
 39. A method according to claim 38, wherein step f) includes the step of: f2) stopping the one end of the moveable bridge at the pre-position.
 40. A method according to claim 38, wherein step f) includes the step of: f2) moving the one end of the moveable bridge through the pre-position at the reduced rate of approach.
 41. A method according to claim 36, comprising the steps prior to step b) of: a1) determining a distance of the aircraft relative to the one end of the moveable bridge; and, a2) when the determined distance is less than a predetermined threshold value, automatically moving the one end of the moveable bridge to a predetermined safe position.
 42. A method according to claim 35, wherein the imager comprises a laser imager. 